1. Field of the Invention
The present invention relates to a plasma processing apparatus and a processing method utilized for producing a semiconductor device, a liquid crystal panel, a solar cell, and the like, and more specifically to a plasma processing apparatus and a processing method utilized for various kinds of fine pattern technologies such as a thin-film deposition process and a dry etching process.
2. Description of the Related Art
In recent years, much active effort has been made in order to improve the performance of a device to be produced and reduce the necessary processing cost thereof. The objectives of such efforts are to improve the quality of the device; accelerate the processing rate; enlarge the processing area; and reduce the damage given to the device to be processed by the apparatus.
Japanese Patent Publications Nos. 62-43335, 53-44795 and 53-34461 disclose conventional microwave plasma processing apparatuses. However, since these microwave plasma processing apparatuses employ an electromagnet coil, such apparatuses become disadvantageously bulky in processing a large substrate. In addition, such apparatuses cannot process a substrate so uniformly.
Japanese Laid-Open Patent Publication No. 62-5600 discloses another conventional microwave plasma processing apparatus capable of processing a relatively large substrate. According to the technique described in this Patent Publication, the uniformity of the plasma processing is satisfactorily high in the propagating direction of the microwave. However, in the width direction perpendicular to the propagating direction of the microwave, the substrate is not exposed uniformly to the plasma, that is, the plasma density in the central portion of the substrate is high, while the density of the plasma in the end portions is low. Accordingly, such an apparatus is unable to process a large substrate for a solar cell, a liquid crystal panel, and the like entirely at one time. Moreover, since the area of the plasma generator facing the substrate to be processed is larger than that of the substrate to be processed, it is difficult to mount such a generator on a multi-chambered type apparatus.
U.S. Pat. No. 5,234,565 also relates to a microwave plasma processing apparatus. According to the technique disclosed in this patent, however, a microwave is radiated from a coaxial open end, so that the microwave has a high electric field intensity in the central portion of an inner conductor of a coaxial waveguide. Accordingly, such ununiform distribution of the microwave makes the density of the plasma ununiform, too. As a result, such an apparatus is unable to process a large substrate uniformly.